Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 458 insertions, 0 deletions

diff --git a/fs/minix/dir.c b/fs/minix/dir.c
new file mode 100644
index 000000000..2ca16f849
--- /dev/null
+++ b/fs/minix/dir.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ *  minix directory handling functions
+ *
+ *  Updated to filesystem version 3 by Daniel Aragones
+ */
+
+#include "minix.h"
+#include <linux/buffer_head.h>
+#include <linux/highmem.h>
+#include <linux/swap.h>
+
+typedef struct minix_dir_entry minix_dirent;
+typedef struct minix3_dir_entry minix3_dirent;
+
+static int minix_readdir(struct file *, struct dir_context *);
+
+const struct file_operations minix_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= minix_readdir,
+	.fsync		= simple_fsync,
+};
+
+/*
+ * Return the offset into page `page_nr' of the last valid
+ * byte in that page, plus one.
+ */
+static unsigned
+minix_last_byte(struct inode *inode, unsigned long page_nr)
+{
+	unsigned last_byte = PAGE_SIZE;
+
+	if (page_nr == (inode->i_size >> PAGE_SHIFT))
+		last_byte = inode->i_size & (PAGE_SIZE - 1);
+	return last_byte;
+}
+
+static void dir_commit_chunk(struct folio *folio, loff_t pos, unsigned len)
+{
+	struct address_space *mapping = folio->mapping;
+	struct inode *dir = mapping->host;
+
+	block_write_end(pos, len, len, folio);
+
+	if (pos+len > dir->i_size) {
+		i_size_write(dir, pos+len);
+		mark_inode_dirty(dir);
+	}
+	folio_unlock(folio);
+}
+
+static int minix_handle_dirsync(struct inode *dir)
+{
+	int err;
+
+	err = filemap_write_and_wait(dir->i_mapping);
+	if (!err)
+		err = sync_inode_metadata(dir, 1);
+	return err;
+}
+
+static void *dir_get_folio(struct inode *dir, unsigned long n,
+		struct folio **foliop)
+{
+	struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL);
+
+	if (IS_ERR(folio))
+		return ERR_CAST(folio);
+	*foliop = folio;
+	return kmap_local_folio(folio, 0);
+}
+
+static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
+{
+	return (void*)((char*)de + sbi->s_dirsize);
+}
+
+static int minix_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	struct minix_sb_info *sbi = minix_sb(sb);
+	unsigned chunk_size = sbi->s_dirsize;
+	unsigned long npages = dir_pages(inode);
+	unsigned long pos = ctx->pos;
+	unsigned offset;
+	unsigned long n;
+
+	ctx->pos = pos = ALIGN(pos, chunk_size);
+	if (pos >= inode->i_size)
+		return 0;
+
+	offset = pos & ~PAGE_MASK;
+	n = pos >> PAGE_SHIFT;
+
+	for ( ; n < npages; n++, offset = 0) {
+		char *p, *kaddr, *limit;
+		struct folio *folio;
+
+		kaddr = dir_get_folio(inode, n, &folio);
+		if (IS_ERR(kaddr))
+			continue;
+		p = kaddr+offset;
+		limit = kaddr + minix_last_byte(inode, n) - chunk_size;
+		for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
+			const char *name;
+			__u32 inumber;
+			if (sbi->s_version == MINIX_V3) {
+				minix3_dirent *de3 = (minix3_dirent *)p;
+				name = de3->name;
+				inumber = de3->inode;
+	 		} else {
+				minix_dirent *de = (minix_dirent *)p;
+				name = de->name;
+				inumber = de->inode;
+			}
+			if (inumber) {
+				unsigned l = strnlen(name, sbi->s_namelen);
+				if (!dir_emit(ctx, name, l,
+					      inumber, DT_UNKNOWN)) {
+					folio_release_kmap(folio, p);
+					return 0;
+				}
+			}
+			ctx->pos += chunk_size;
+		}
+		folio_release_kmap(folio, kaddr);
+	}
+	return 0;
+}
+
+static inline int namecompare(int len, int maxlen,
+	const char * name, const char * buffer)
+{
+	if (len < maxlen && buffer[len])
+		return 0;
+	return !memcmp(name, buffer, len);
+}
+
+/*
+ *	minix_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name.
+ * It does NOT read the inode of the
+ * entry - you'll have to do that yourself if you want to.
+ * 
+ * On Success folio_release_kmap() should be called on *foliop.
+ */
+minix_dirent *minix_find_entry(struct dentry *dentry, struct folio **foliop)
+{
+	const char * name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct inode * dir = d_inode(dentry->d_parent);
+	struct super_block * sb = dir->i_sb;
+	struct minix_sb_info * sbi = minix_sb(sb);
+	unsigned long n;
+	unsigned long npages = dir_pages(dir);
+	char *p;
+
+	char *namx;
+	__u32 inumber;
+
+	for (n = 0; n < npages; n++) {
+		char *kaddr, *limit;
+
+		kaddr = dir_get_folio(dir, n, foliop);
+		if (IS_ERR(kaddr))
+			continue;
+
+		limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
+		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
+			if (sbi->s_version == MINIX_V3) {
+				minix3_dirent *de3 = (minix3_dirent *)p;
+				namx = de3->name;
+				inumber = de3->inode;
+ 			} else {
+				minix_dirent *de = (minix_dirent *)p;
+				namx = de->name;
+				inumber = de->inode;
+			}
+			if (!inumber)
+				continue;
+			if (namecompare(namelen, sbi->s_namelen, name, namx))
+				goto found;
+		}
+		folio_release_kmap(*foliop, kaddr);
+	}
+	return NULL;
+
+found:
+	return (minix_dirent *)p;
+}
+
+int minix_add_link(struct dentry *dentry, struct inode *inode)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	const char * name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct super_block * sb = dir->i_sb;
+	struct minix_sb_info * sbi = minix_sb(sb);
+	struct folio *folio = NULL;
+	unsigned long npages = dir_pages(dir);
+	unsigned long n;
+	char *kaddr, *p;
+	minix_dirent *de;
+	minix3_dirent *de3;
+	loff_t pos;
+	int err;
+	char *namx = NULL;
+	__u32 inumber;
+
+	/*
+	 * We take care of directory expansion in the same loop
+	 * This code plays outside i_size, so it locks the page
+	 * to protect that region.
+	 */
+	for (n = 0; n <= npages; n++) {
+		char *limit, *dir_end;
+
+		kaddr = dir_get_folio(dir, n, &folio);
+		if (IS_ERR(kaddr))
+			return PTR_ERR(kaddr);
+		folio_lock(folio);
+		dir_end = kaddr + minix_last_byte(dir, n);
+		limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
+		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
+			de = (minix_dirent *)p;
+			de3 = (minix3_dirent *)p;
+			if (sbi->s_version == MINIX_V3) {
+				namx = de3->name;
+				inumber = de3->inode;
+		 	} else {
+  				namx = de->name;
+				inumber = de->inode;
+			}
+			if (p == dir_end) {
+				/* We hit i_size */
+				if (sbi->s_version == MINIX_V3)
+					de3->inode = 0;
+		 		else
+					de->inode = 0;
+				goto got_it;
+			}
+			if (!inumber)
+				goto got_it;
+			err = -EEXIST;
+			if (namecompare(namelen, sbi->s_namelen, name, namx))
+				goto out_unlock;
+		}
+		folio_unlock(folio);
+		folio_release_kmap(folio, kaddr);
+	}
+	BUG();
+	return -EINVAL;
+
+got_it:
+	pos = folio_pos(folio) + offset_in_folio(folio, p);
+	err = minix_prepare_chunk(folio, pos, sbi->s_dirsize);
+	if (err)
+		goto out_unlock;
+	memcpy (namx, name, namelen);
+	if (sbi->s_version == MINIX_V3) {
+		memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
+		de3->inode = inode->i_ino;
+	} else {
+		memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
+		de->inode = inode->i_ino;
+	}
+	dir_commit_chunk(folio, pos, sbi->s_dirsize);
+	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
+	mark_inode_dirty(dir);
+	err = minix_handle_dirsync(dir);
+out_put:
+	folio_release_kmap(folio, kaddr);
+	return err;
+out_unlock:
+	folio_unlock(folio);
+	goto out_put;
+}
+
+int minix_delete_entry(struct minix_dir_entry *de, struct folio *folio)
+{
+	struct inode *inode = folio->mapping->host;
+	loff_t pos = folio_pos(folio) + offset_in_folio(folio, de);
+	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
+	unsigned len = sbi->s_dirsize;
+	int err;
+
+	folio_lock(folio);
+	err = minix_prepare_chunk(folio, pos, len);
+	if (err) {
+		folio_unlock(folio);
+		return err;
+	}
+	if (sbi->s_version == MINIX_V3)
+		((minix3_dirent *)de)->inode = 0;
+	else
+		de->inode = 0;
+	dir_commit_chunk(folio, pos, len);
+	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
+	mark_inode_dirty(inode);
+	return minix_handle_dirsync(inode);
+}
+
+int minix_make_empty(struct inode *inode, struct inode *dir)
+{
+	struct folio *folio = filemap_grab_folio(inode->i_mapping, 0);
+	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
+	char *kaddr;
+	int err;
+
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	err = minix_prepare_chunk(folio, 0, 2 * sbi->s_dirsize);
+	if (err) {
+		folio_unlock(folio);
+		goto fail;
+	}
+
+	kaddr = kmap_local_folio(folio, 0);
+	memset(kaddr, 0, folio_size(folio));
+
+	if (sbi->s_version == MINIX_V3) {
+		minix3_dirent *de3 = (minix3_dirent *)kaddr;
+
+		de3->inode = inode->i_ino;
+		strcpy(de3->name, ".");
+		de3 = minix_next_entry(de3, sbi);
+		de3->inode = dir->i_ino;
+		strcpy(de3->name, "..");
+	} else {
+		minix_dirent *de = (minix_dirent *)kaddr;
+
+		de->inode = inode->i_ino;
+		strcpy(de->name, ".");
+		de = minix_next_entry(de, sbi);
+		de->inode = dir->i_ino;
+		strcpy(de->name, "..");
+	}
+	kunmap_local(kaddr);
+
+	dir_commit_chunk(folio, 0, 2 * sbi->s_dirsize);
+	err = minix_handle_dirsync(inode);
+fail:
+	folio_put(folio);
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int minix_empty_dir(struct inode * inode)
+{
+	struct folio *folio = NULL;
+	unsigned long i, npages = dir_pages(inode);
+	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
+	char *name, *kaddr;
+	__u32 inumber;
+
+	for (i = 0; i < npages; i++) {
+		char *p, *limit;
+
+		kaddr = dir_get_folio(inode, i, &folio);
+		if (IS_ERR(kaddr))
+			continue;
+
+		limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
+		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
+			if (sbi->s_version == MINIX_V3) {
+				minix3_dirent *de3 = (minix3_dirent *)p;
+				name = de3->name;
+				inumber = de3->inode;
+			} else {
+				minix_dirent *de = (minix_dirent *)p;
+				name = de->name;
+				inumber = de->inode;
+			}
+
+			if (inumber != 0) {
+				/* check for . and .. */
+				if (name[0] != '.')
+					goto not_empty;
+				if (!name[1]) {
+					if (inumber != inode->i_ino)
+						goto not_empty;
+				} else if (name[1] != '.')
+					goto not_empty;
+				else if (name[2])
+					goto not_empty;
+			}
+		}
+		folio_release_kmap(folio, kaddr);
+	}
+	return 1;
+
+not_empty:
+	folio_release_kmap(folio, kaddr);
+	return 0;
+}
+
+/* Releases the page */
+int minix_set_link(struct minix_dir_entry *de, struct folio *folio,
+		struct inode *inode)
+{
+	struct inode *dir = folio->mapping->host;
+	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
+	loff_t pos = folio_pos(folio) + offset_in_folio(folio, de);
+	int err;
+
+	folio_lock(folio);
+	err = minix_prepare_chunk(folio, pos, sbi->s_dirsize);
+	if (err) {
+		folio_unlock(folio);
+		return err;
+	}
+	if (sbi->s_version == MINIX_V3)
+		((minix3_dirent *)de)->inode = inode->i_ino;
+	else
+		de->inode = inode->i_ino;
+	dir_commit_chunk(folio, pos, sbi->s_dirsize);
+	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
+	mark_inode_dirty(dir);
+	return minix_handle_dirsync(dir);
+}
+
+struct minix_dir_entry *minix_dotdot(struct inode *dir, struct folio **foliop)
+{
+	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
+	struct minix_dir_entry *de = dir_get_folio(dir, 0, foliop);
+
+	if (!IS_ERR(de))
+		return minix_next_entry(de, sbi);
+	return NULL;
+}
+
+ino_t minix_inode_by_name(struct dentry *dentry)
+{
+	struct folio *folio;
+	struct minix_dir_entry *de = minix_find_entry(dentry, &folio);
+	ino_t res = 0;
+
+	if (de) {
+		struct inode *inode = folio->mapping->host;
+		struct minix_sb_info *sbi = minix_sb(inode->i_sb);
+
+		if (sbi->s_version == MINIX_V3)
+			res = ((minix3_dirent *) de)->inode;
+		else
+			res = de->inode;
+		folio_release_kmap(folio, de);
+	}
+	return res;
+}